During his inaugural address earlier this week, President Obama raised eyebrows by making a call for new action on climate change.

“We will respond to the threat of climate change, knowing that the failure to do so would betray our children and future generations,” he said.

But given the tricky politics of climate change in Washington – Democrats were unable to pass cap-and-trade legislation when they controlled both the White House and Congress – environmental groups are urging the Obama administration to avoid Congress and pursue executive action.

“Congress has proved to be the place where good ideas go to die, and clearly the climate bill’s failure back in 2009 is an example of that,” said Melinda Pierce, legislative director for the Sierra Club.

Obama acknowledged the difficulty of getting climate legislation passed when he was asked about it during a Nov. 14 press conference. “I don't know what either Democrats or Republicans are prepared to do at this point,” he said.

But environmental activists say the president has already taken steps outside Congress, pointing to the work done on fuel efficiency standards that the Environmental Protection Agency and Department of Transportation adopted in 2012.

To build on that, green groups are urging the president to use the EPA’s authority under the Clean Air Act to put emission restrictions on existing power plants.

“He’s already tackled cars,” said Bob Keefe, senior press secretary for the National Resource Defense Council. “Now we need to go after this other big source of carbon pollution.”

This isn’t a new proposal – it’s been an option ever since the Supreme Court ruled in 2007 that the E.P.A. had an obligation, under the Clean Air Act, to regulate greenhouse gases that contribute to climate change unless it could find a scientific reason for not regulating them.

And while the EPA is already working on carbon restrictions for new power plants (final proposals for which are due in April 2013), environmental groups have used the milestone of President Obama’s second term to stage a new campaign urging him to make existing plants subject to emissions caps as well.

“That’s probably our number one issue right now,” Keefe said.

The NRDC held a press conference in December to refocus attention on existing power plants and was one of 70 environmental groups that signed a January 7th letter congratulating the president on his re-election and urging him to propose standards for existing plants.

“Use your executive authority,” they wrote, telling him that “most significantly, you can set standards that cut carbon pollution from America’s aging power plant fleet.”

According to the NRDC, imposing restrictions onexisting plants would cut carbon pollution from existing plants by 26 percent from 2005 levels by 2020.

And the Sierra Club is also staging a push that coincides with the beginning of Obama’s second term. Earlier this month, it launched a 100-day campaign to raise awareness for what its branded his “Climate and Clean Energy Legacy,” which includes action on emissions standards on refineries and heavy-duty trucks, stopping the Keystone XL pipeline and limiting expansion of drilling and mining on public lands.

Action on any of these fronts would likely be met with serious resistance from the private sector.

The National Association of Manufacturers – one of the largest manufacturing trade groups in the U.S. – is already lobbying against the proposed EPA restrictions on new power plants. Those efforts would extend to regulations on existing plants, said Ross Eisenberg, NAM’S vice president of energy and resources policy.

“I have a feeling that this will be very, very high priority for us if it does happen,” he said, noting that it’s difficult for the group to forecast exactly what kind of caps the administration would seek to impose. “When you have regulations under the Clean Air Act that almost certainly will impact the economy, we’re going to have a problem with that.”

President Obama also will have several empty cabinet positions to fill that deal with the environment, including the EPA, the Department of Interior and the National Oceanic and Atmospheric Administration. Green groups are already working to get their favored candidates considered; an early favorite for Interior is Rep. Raúl Grijalva (D-AZ), former chairman of the House Subcommittee on National Parks, Forests and Public Lands.

In a December letter to President Obama, a coalition of 238 environmental groups also appealed to the president’s sense of legacy, urging him to “seize this historic opportunity” to appoint a leader “who grasps both the urgency of this crisis and the practical paths towards real-world solutions.”

But while environmental groups are encouraging the president to pursue action through the myriad departments and cabinet offices that make up his administration, one thing is certain: going through Congress is no longer part of the conversation.

“Obviously it would be better to do it with the help of Congress, but he doesn’t have to,” Keene said.